Display panel or portion thereof with a graphical user interface



The sole FIGURE is a front view of a display panel or portion thereofwith a graphical user interface showing our design.

The outermost broken line rectangle illustrates a display panel orportion thereof that forms no part of the claimed design. The remainingbroken lines illustrate portions of the graphical user interface or amixed reality environment and form no part of the claimed design.

CLAIM The ornamental design for a display panel or portion thereof witha graphical user interface, as shown and described.